Single circuit water tube boiler



Oct. 27, 1931. c. E. LUCKE 1,828,814

SINGLE CIRCUIT WATER TUBE BOILER Filed Jan. 3, 1927 5 Sheets-Sheet 1Fig! fiMINVENTOR BY FUZVMZORNEY6 Oct.27, 1931; c. E. LUCKE STNGLECIRCUIT WATER TUBE BOILER- 3 Sheets-Sheet 2 Filed Jan. 5, 19,27

m i AQ; INVENTOR I BY 7 ATTORNEYS Oct. 27, 1931. c. E. LucKE ,8 8,81

SINGLE CIRCIJIT WATER TUBE BOILER Filed Jan. 3. 1927 5'Sheets-Sheet 5 0O O 0 O 0 0 0 0'0 0 0 0 0'0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 vINVENTOR BY W JM ATTORNEYS Patented Oct. 27, 1931 UNITED STATES PATENT?OFFICE CHARLES E. LUCKE, OF NEW YORK, N. Y., ASSIGNOR TO THE BAIBCOGK &WILCOX COM- PANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEYSINGLE CIRCUIT WATER TUBE BOILER Application filed January 3, 1927.Serial No. 158,468.

This invention relates to steam boilers of the forced circulation seriestype, in which there are water tubes connected end to end through whichwater is forced by means of a pump which feeds water to replace steamproduced and also operates as a circulating pump to circulateunvaporized water that has already passed through the tubes. T hepumpfor circulating the water through the tubes receives the water to becirculated from a separator which, in turn, receives steam and excess orunvaporized water from the tubes. Control of the amount of waterwithdrawn from the separator for circulation is by means other than ableeding orifice that would discharge water at a su tantially constantrate and therefore result in a wide variation in the ratio ofcirculation to boiler feed. The means provided herein for controllingthe circulation rate is such as to increase circulat-ion as evaporationand feed are increased, and to assure positive circulation by making itdepend on a pump.

The invention will be understood from the description in connection withthe accomtube connectors; 'Fig. 7 is a vertical section of amodification of tube arrangement showing a furnace with tubes in itssides associated with coils filling the hot gas passageway and Fig. 8 isa section along the line 88 of Fig. 7 partly broken away.

In the drawings, reference character 1 indicates a pump that is used forforcing feed water into the water tubes, and also for circulating theexcess or unvaporized water therethrough. This pump is provided with acylinder 1a that is operated by water under pressure, cylinder 1?) thatis operated by steam from the steam main and cylinder 10 that forceswater into the tubes. The feed water to be forced into the tubes toreplace steam that has been made is drawn through the suction pipe 2from the water supply tank 3 below'the pump. The hot water from thecylinder 1a of the pump passes through the coil 4 and into the tank,while steam from the cylinder 16 passes through the coil 5 into the sametank. Feed water is supplied to the tank 3 through the pipe 6 that isprovided with a float valve 7 for regulating the level of water in thetank. After the water has been forced through'the boiler and some of ithas become evaporated into steam, the mixture of steam and water thatresults passes to a separator 8 in the bottom of which the watercollects and from which it passes through the cylinder 1a of the pump,while the steam passes to the steam main 9 that is provided with avalve. A safety valve 10 of the usual type is provided. Steam passesthrough the pipe 11 that is provided with a valve 12 to the steamcylinder 11) of the pump.

' The valve 12 is controlled by a float 13 in the separator 8 by meansof a chain 14 and the sprockets 15 and 16, so that as the water levelfalls in the separator due to an increase in steam produced inproportion to boiler feed,-the valve 12 is opened by the.

falling float to make the pump run faster. At the same time an increasedamount of water per minute will be withdrawn from the separator 8 by thecylinder 1a, discharged into' the tank 3 and returned to the tubes witha proportionate amount of new feed water by cylinder 10 which has alarger displacement than 1a by the amount of feed water per stroke.

The pump forces water from the feed tank 3 through pipe 18 to adistributing header 19 that is provided with handholes 20. A row oftubes 21 leads from the distributing header 19 across the hot gaspassage from the furnace, and their ends are connected by connectors 22to another row of tubes that likewise extend across the hot gas passageand have their ends connected 'to another row, and so on, thus providinga number of vertical rows of tubes across the furnace, which areconnected by pipes 23 to a header 24 that is provided with handholes 25.in this way sets of tubes are provided with their ends connected, thusforming what may be termed coils, in this case flat coils of straighttubes that can be internally inspected and easily cleaned. The severalcoils in this illustra tion are connected in parallel, each coilreceiving water from the distributing header 19 and delivering steam andwater to the collector 24. The collector 24 is connected by a pipe 26 tothe steam and water separator 8, and the collector 24 is also providedwith a top vent connection 27 to the steam space of the separator 8 tofacilitate smooth flow and to aid in separating steam and water. i

The tube connectors 22 for connecting the ends of the tubes in thisillustration are shown in detail in Figs. 2 and 3. The ends of thesemi-circular connector 22 are provided with laterally extending lugs22a that are provided with holes through which bolts 28 extend, andconnect the connectors to the rings 29 that are threaded upon the endsof the tubes 21 and are provided with laterally extending lugs 29a withholes therein to receive the bolts 28. Packing rings 30 may be locatedbetween the ends of the tubes 21 and seats provided therefor in the endsof the connectors 22.

The tubes 21 extend across a hot gas passage whose walls are shown at31, so that hot gases from the furnace below contact with the tubes andgenerate steam in them. The furnace may be heated in any convenientmanner. It is illustrated as being heated by means of fuel burners 32.

To meet varying conditions of practice the tube and coil arrangementscan be modified .so as to produce results that will be best for anygiven circumstances without departing from the major features of thesystem of steam generation with pump circulation controlled to keep pacewith boiler load. The tubes may be straight or curved, the former beingbest for conditionswhere scale.may be deposited, while the latter havesome advantage in subdivision of gas stream and in reducing thestress'between two fixed points due to expansion, and may be used whenscale does not deposit. The tube connectors may of flow resistance andpump work. By put- Referring to Fig. 1, there are nineteen tubes I shownin series in one vertical flat coil and as many such fiat coils inparallel as may be desirable are placed side by side in the gas passage.In Figs. 4 and 5' there are shown nine tubes in series in one horizontallayer and nineteen such layers in series, thus providing one hundred andseventy one tubes all in series.

When the water delivered by the pump to the tubes is much below theboiling point for the boiler pressure, it is advantageous to feed thewater in a generally countercurrent direction with reference to the hotgases. This is indicated in the drawings, but it is not essential, andbecomes of lesser advantage as the water supply becomes hotter. Afterthe water flowing through the tubes has reached steam temperature anydirection of flow may be used with no heat absorbent advantage one wayas compared with another, so arrangement of flow may be selected withreference to convenience or advantage in other directions.

As the gases cool in their flow across the water tubes the temperaturedifference between gases and water will become less. and the heatabsorbed per square foot will decrease in proportion. It is possible toget more capacity from this heating surface by increasing the mass flowof the gases and this is conveniently done by decreasing the crosssection of the gas passage in the direction of gas flow.

In the modificationshown in Figs. 4 and 5, the coils of the tubes extendhorizontal across the furnace instead of vertically, as illustrated inFig. 1, and the tubes are bent along semi-circular arcs. Feed water fromthe pump passes through the pipe 18 to the upper compartment of thevertically-disposed distributing header 36. from which it passes to theuppermost coil 37. back and forth across the furnace to the uppercompartment 38 of the vertically-disposed header 39, thence into thenext coil, as most clearly shown in Fig. 6, thence zig-zag across thefurnace to the header 36 into the next lower coil, and so on, until themixture of steam and Water passes through the. pipe 23 into the header24 and then to the separator. The headers 36 and 39 are provided atintervals with partitions 40 and "with handholes 41, as shown in Fig. 6.In the modification shown in Figs. 4 and 5, the water passes in seriesthrough all the tubes that extend across the hot gas passage.

In the modification shown in Figs. 7 and 8, the pipe 18 from the pump isconnected toa distributing header 42, from which one or more rows oftubes 43 extend to a similar header 44. This header 44 is connected byshort nipples 45 to a similar header l0 cated below it, from whichheader one or more rows of tubes extend to a header located below theheader 42 that is connected by nipples to a lower header, and so on. Inthis way, two sides of a flue are formed by the headers 42 and 44 andthe tubes 43 extend across the flue. In this modification, two rows oftubes are shown connecting each pair of headers near the upper end ofthe flue, and only one row of tubes connects the other pairs of headers.The headers are made progressively longer toward the bottom of the flue,and the tubes connecting the headers are made progressively larger. Thelowermost header 44 is connected by nipples 46,to a header 47 from whichheadera row of tubes 48 extends across the top of the furnace into aheader 49, thus forming a slag screen. The header 49 is connected by thetubes 50 to a. header 51, from which a row of tubes 52 which form aWater screen leads to the header 53 that is connected by means 0 thepipe 23 to the collector 24.

In boilers constructed in accordance with this invention, the forcedcirculation provided by the pump will insure a high enough velocity inall tubes to materially reduce scale deposition or. eliminate it, andwill also insure that all heated tube surface is regularly wetted by theexcess of water circulated over what is evaporated and so the surface ismade safe against burns. Tube sizes, number and arrangement may beselected wholly without regard to the limitations that are usualinboilers with natural circulation, so that boilers constructed inaccordance with the present" invention may be suitable for conditions ofservice of wider range. I claim:

1. The process of steam generation which comprises forcing water inexcess through a heated zone, withdrawing steam and unevaporated waterfrom said zone, separating said steam and water and utilizing saidseparated water in the forcing of water through said zone.

2. The process of steam generation which comprises forcing water inexcess through a Y heated zone, separating the steam'and water from saidzone, reducing the pressure on the separated water to atmosphericpressure, and circulating it together with fresh feed Water through the"zone, the amount of circulating'water and fresh feed water varyingdirectly with, each other? 3. A process of generating steam whichincludes forcing an excess of water under pressure through a heating andsteam generating zone, separating the steam so generated from theunevaporate-d water, utilizing the unevaporated water under pressure foraiding in the forcing of the water through said zone, decreasing thepressure of said unevaporated water to a pressure below that of thewater in the zone and mixing said unevaporated waterwith additionalwater before it enters the zone.

4. The combination with a water tube boiler of a steam and waterseparator for receivmg a mlxture of steam and water therefrom. a steamand water driven pump for feeding water through said tubes, means forutilizing both steam and water from said separator for operating saidpump, and means for combining the exhaust from the steam and waterdriven means of said pump with fresh feed water.

5. The combination with a water tube boiler of a steam and waterseparator for receiving a mixture of steam and water therefrom, a waterdriven feed pump for forcing water through said tubes, means forbleeding water from said separator and delivering said bleed water tothe driven part of said pump, and means for mixing said bleed water withthe feed water supplied to said pump.

6. The combination with a water tube boiler of a steam and waterseparator for receiving a mixture of steam and water therefrom, a feedpump for forcing water through from, a water driven pump for feedingwater through said tubes and means for bleeding from said separator tosaid econd cylinder and for subsequently mixing said bleed water withthe feed water entering said feed cylinder, said cylinders being soarranged as to maintain a fixed relationship between the volume of waterbled from said separator and the volume of feed water delivered to saidpump.

9. The. combination with a water tube boiler of a steam and waterseparator for receivios - water from said separator and utilizing thefrom, a feed pump for forcing water through said boiler, a feed watertank under atmospheric pressure for delivering feed water to said pump,separate operating cylinders for said pump, means for delivering steamfrom said separator to one of said cylinders, means for delivering waterfrom said separator to the other of said cylinders, and means fordelivering the exhaust from each r of said cylinders to the feed waterin said tank.

11. The combination with a water tube boiler of a steam and waterseparator for receiving a mix are of steam and water therefrom, a feedpump for forcing water through said boiler, separate operating cylindersfor operating said feed pump, means for delivering steam from saidseparator to one of said cylinders, means for delivering water from saidseparator to the other of said cylinders,

'and means for varying the delivery of steam to said steam cylinder byand in accordance with variations in the water level, in said separator.

12. A forced circulation boiler including a plurality of series flowconduits, and pumping means delivering water through all of saidconduits and automatically maintaining a predetermined relationshipbetween the volume of water circulated and the volume of waterevaporated, said pumping means .being proportioned so that the volume ofwater circulated continuously exceeds the volume of water evaporated.

13. A forced circulation boiler including a plurality of series flowconduits, and pumping means delivering water through all of saidconduits and automatically maintaining a fixed predeterminedrelationship between the volume of water circulated and the volume ofwater evaporated, said pumping means being proportioned so that thevolume of volume of water circulated continuously exceeds the volume ofwater evaporated.

15. A forced circulation boiler in combination with means maintaining apredetermined relationship between the volume of water circulated andthe volume of water evaporated, said ,means including a water drivenpump having a driving and a driven end, the driving end connected toreceive its operating water from the boiler circuit, a source of makeupwater connected to the driven end of said pump, a discharge lineconnected between said source and the driving end of said pump fordelivering water exhausted from said driving end to said source, thecapacity of the driven end being larger than that of the driving endwhereby the volume of water circulated is greater than that evaporated.

16. A forced circulation boiler in combination with means maintaining a.predetermined relation between the volume of water circulated and thevolume of water evaporated, said means including a water driven pumphaving a driving and a driven end, means leading the water from theboiler circuit through the driving end to actuate the same anddischarging into areceiving means, a source of make-up water, aconnection between the driven end of said pump and said 5 receiver and aconnection between the discharge of the driven end of said pump and theboiler, the relative capacities of the driving and driven ends of saidpump being in a ratio to deliver the combined volume from the receiverto the boiler.

CHARLES E. LUCKE.

water circulated continuously exceeds the I volume of water evaporated.I

14. A forced circulation boiler including a plurality of series flowconduits, and pumping means delivering water through all of saidconduits and automatically maintaining a predetermined minimumrelationship between the volume of water circulated and the volume ofwater evaporated, said pumping means being proportioned so that the

